Heat exchanger



FIG. 1 is a perspective view of a heat exchanger showing our new design.

FIG. 2 is a top view thereof.

FIG. 3 is a bottom view thereof.

FIG. 4 is a rear view thereof.

FIG. 5 is a front view thereof.

FIG. 6 is a left side view thereof.

FIG. 7 is a right side view thereof.

FIG. 8 is a perspective view of another embodiment of the heatexchanger.

FIG. 9 is a top view thereof.

FIG. 10 is a bottom view thereof.

FIG. 11 is a rear view thereof.

FIG. 12 is a front view thereof.

FIG. 13 is a left side view thereof; and,

FIG. 14 is a right side view thereof.

The broken line shown in the drawings are for the purpose ofillustrating portions of the article that form no part of the claimeddesign.

CLAIM The ornamental design for a heat exchanger, as shown anddescribed.